The invention relates to a blood exchange apparatus or rather dialyzer comprising a plurality of layers each including a membrane envelope and an intermediate netting layer enclosed by said membrane envelope. The layers are held spaced from each other at a small distance by spacers. Blood is conducted between adjacent layers and an exchange liquid is conducted within the intermediate netting layers.
Such dialyzer devices have been constructed in accordance with the original suggestions of Hoeltzenbein and according to the principle of Guarino.
Such known dialyzer devices operate according to the cross flow principle. This entails the disadvantage that the masses which are transported through the exchange surfaces of the membrane are small as compared to the counter-current and that the exchange distance is relatively small.
The spacing between the layers is produced by an applied adhesive mass which sets within a short time. In this connection there is the disadvantage that the edges of the adhesive mass cannot always be produced cleanly along a straight line so that dead corners occur in these areas in which blood residues may settle and coagulate. Such blood exchange devices are used as dialyzers, hemofilters, and other similar medical applications. However, it is conceivable to use exchange devices constructed basically in the same manner also in chemical process technology.
The production of known blood exchange devices has been mainly performed by hand heretofore which disadvantageously affects the price.